Lasers are widely used today in various communications systems including in fiber-optic communications systems laid across large bodies of water. In such systems, laser modules are positioned underwater at various points along the fiber-optic cable to amplify the transmitted signals, thereby enabling such signals to be transmitted over long distances. However, when one of these laser modules malfunctions, millions of dollars must typically be expended to replace the faulty module since a properly manned and equipped ship must be launched to do so. In addition, millions of dollars may also be lost since the communications system can not generate revenue when it is off line as a result of the malfunctioning module. Accordingly, it is important that laser modules selected for use operate according to specification and not malfunction.
Towards this end, companies typically test fabricated fiber-optic laser modules to determine which modules are likely to malfunction before their projected lifetime and should therefore not be used. Conventional methods employed for such tests typically analyze the change over time in the coupling efficiency, i.e. power out, of each laser module during a burn-in period. However, such conventional methods suffer from a significant drawback. Specifically, while analyzing the change in the coupling efficiency will identify those modules which have already begun to malfunction, such testing will not accurately identify those modules which, although performing according to specification at the time of the test, are likely to malfunction in the future because the fiber tip has begun to move relative to the laser at an unacceptable rate of displacement
It is therefore, an object of the present invention to provide an improved method for quality assurance testing of fiber-optic laser modules which overcomes the foregoing drawback to more reliably determine which laser modules are likely to malfunction and should therefore not be used.